Health Risks  

Nickel, is an essential natural element that constitutes approximately 0.009% of the earth's crust. It exists as components of other minerals; Nickel sulfides, silicates and oxides^[a] are three of the most important nickel minerals from a mining and natural resource perspective [EPA paper, source 2]. The most common nickel sulfide mineral is pentlandite [(NiFe)9S8] accounts for the majority of nickel produced globally [source 4,5]. 40% of domestic nickel production comes from the smelting of natural nickel ores or refining nickel matte, an impure metallic sulfide product from smelting of sulfides of metal ores. The other 60% of domestic nickel production comes from reclamation of nickel metal from nickel based or non-nickel based scrap metal, including salvaged machinery, sheet metal, aircraft and other vehicular parts and discarded consumer goods such as batteries

Nickel compounds are used in construction, mining, smelting, electrical equipment manufacturing, and battery and fuel cell production, among numerous other materials. During construction, there is a high risk for nickel contamination. They can also make their way into the household through ceramics since they often form the bond between enamel and iron.

Nickel compounds are so toxic because they are highly resistant to corrosion and oxidation in air and aqueous environments; they are resistant to corrosion by organic acids and exposure to chlorine, fluorine, hydrogen chloride and molten salts. However, extremely oxidizing acids like nitric acid can often do the trick to break down nickel compounds.

Est. average daily dietary intake is 0.1-0.3 mg/day [AUS sources 7,8] Less than 0.2 mg/day of which is consumed via food and 5-25 ug/day from water [AUS source 4]. Dermal exposure is one of the most common routes of exposure and even low levels of exposure may cause nickel allergic dermatitis. Susceptibility to nickel increases with age [AUS sources 16-18]

Common Effects:[1]

Gastrointestinal distress like: nausea, vomiting, and diarrhea

Dermatitis (eczema like effects: rash, itchiness)

Neurological effects

Nickel specific asthma

[1] "Nickel Compounds." EPA. Environmental Protection Agency, n.d. Web. 13 Oct. 2014. <http://www.epa.gov/ttnatw01/hlthef/nickel.html>.

Case Study:

In 2004 Sampleton, New South Wales, Australia observed a huge spike in nickel concentration in their drinking water. (See graph) Although scientists don't know the exact reasons for how nickel concentrations increased so dramatically, as shown in figure 1, they hypothesize that it could be the result of a natural reduction of flow rate during a period of drought and the subsequent introduction of mine water into the drinking water supply. Overall fluctuations of nickel concentrations over the three years were attributed to natural dilution and changes in demands of water.

The Australian Drinking Water Guidelines mandates a safety threshold of  0.02 mg Ni/L water, a value that is based on 70 kg (154 lbs) average body weight, 2 L water consumed daily and 1000 as the safety factor to account for uncertainty of extending animal study results to humans. The residents of Sampleton are assumed to have a similar diet to the rest of Australia's population so that the results of the study can be extended to the whole country. The study also assumed that the entire population of Sampleton was nickel-sensitive. This would lead to a lower Lowest Observed Adverse Effect Level (LOAEL) and set stricter limit for tolerable mean nickel concentrations. The result of the study showed that the mean nickel concentration, 0.03 mg/L with a 95% confidence interval of 0.02-0.04 mg/L, is only approximately 7% of the LOAEL. Thus the mean nickel concentration in drinking water in Sampleton appears to have no health risks.

Although no real risks were detected, the town implemented increased surveillance of nickel concentrations and made plans to use alternative sources to supplement drinking water supplies during droughts. This study shows the importance of continued vigilance in maintaining high water quality standards at all times, had the concentration of nickel increased past the LOAEL, health effects could have been more drastic. [2]

[2]Alam, Noore, Stephen J. Corbett, and Helen C. Ptolemy. "Environmental Health Risk Assessment of Nickel Contamination of Drinking Water in a County Town in NSW." NSW Public Health Bulletin (2008): n. pag. Web. <http://www.publish.csiro.au/?act=view_file&file_id=NB97043.pdf>.

Current Remediation Techniques

• Cyclic electrowinning/precipitation (CEP) : use of electrical current to transform positively charged metal cations into a stable, solid state where they can be easily separated from water and removed

Drawback: concentration of cations must be high (threshold of 100 ppm)

• Chemical precipitation: use of hydroxides and sulfides to precipitate cations  

Precipitation with sulfide reported to be the most efficient because of its low solubility to             destabilize soluble complexes

Advantages:

1. Well-established, many available chemicals and equipment

2.  Convenient, self-operating and low-maintenance due to closed system nature

Disadvantages:

1. Formation of toxic sludge from precipitate, which is environmentally and economically costly to remove

            2. Requires extra flocculation/coagulation due to precipitation

            3. Each metal has a distinct pH for optimum precipitation

            4. Corrosive chemicals increases safety concerns

• Ion exchange: reversible chemical reaction where ions from water or wastewater solution are exchanged for similarly charged ions attached to a stationary solid particle that are usually inorganic zeolites or resins

• Reverse osmosis: effective molecular filter to remove dissolved solutes through a membrane

Advantages:

1. Reduces concentration of all ionic contaminants, not just the heavy metal in question

2. Can be scaled up easily

Disadvantages:

1. Expensive

2. Requires high pressure

3. Too sensitive to operating conditions

• Phytoremediation: use of plants to remediate heavy metals in contaminated soil, sludge, water etc.

• Microbial remediation: use of microorganisms to degrade hazardous contaminants

Advantages:

1. Cheap

2. Environmentally safe and positive public reception

3. Does not generate waste

4. Self-sustaining

5. Can be used in conjunction with other technology

Disadvantages:

1. May be limited to which contaminants can be targeted

2. Long time scale

            3. Biological processes are very specific

            4. Difficult to scale up

The figure below [Fig. 2 from EPA paper] shows the variety of ways nickel compounds can be utilized.

Anthropogenic Nickel contamination can occur in a variety of ways:

• Direct : producing nickel or consuming nickel or nickel compounds to manufacture usable products          

• Nickel ore mining and smelting
• Nickel matte refining
• Electroplating
• Battery manufacturing        

• Indirect : not producing nickel or nickel-containing products but inadvertently handling nickel because it is present as an impurity

• Metal pipes and fittings coming into contact with drinking water
• Coal and oil supplying and combustion
• Municipal refuse and sewage sludge incineration
• Petroleum processing
• Indirect sources is the cause of 85-94% of total anthropogenic atmospheric nickel emissions [sources 3, 4, 5]

Nickel emission differs by geographic region, as indicated by the following figure:

Health Risks

• Nickel carbonyl Ni(CO)4 formation

• Ni(CO)4 is a colorless or slightly yellow liquid formed by direct combination of metallic nickel and carbon monoxide.
• Ni(CO)4 is a highly unstable compound and will dissociate with a half life of a            hundred seconds.
• The carbon monoxide released from dissociation poses a major health risk.

• Health effects depend on many factors [AUS sources 4, 11-13]

• Route of administration
• Water solubility of nickel compounds
• Dose
• Body weight
• Sensitivity
• Duration of exposure

• Dermal exposure is one of the most common routes of exposure and even low levels of exposure may cause nickel allergic dermatitis. Susceptibility to nickel increases with age [AUS sources 16-18]

• Females are much more prone to this dermatitis than males.
• According to a study by the Expert Group on Vitamins and Minerals, approximately 7-10% of   the population in the United Kingdom suffer from this condition [AUS source 15].

• Variations in severity due to differences in sensitivity

• Differences in sensitivity lead to wide variations in nickel concentrations in blood and urine [AUS source 7]
• Difficult to assess the dose-response relationship (how the response varies with increasing dose)
• Lowest Observed Adverse Effect Level (LOAEL) for oral dose ~ 0.05 mg/kg body weight when skin is not sensitized [AUS source 8] but can decrease to 0.012 mg/kg when the skin is sensitized [AUS source 13]. These doses correspond to the concentrations that provoke dermatitis.

Case Study

Consider "Environmental health risk assessment of nickel contamination of drinking water in a county town in NSW" -- Noore Alam, Stephen J. Corbett, Helen C. Ptolemy

Location: Small country town named Sampleton (contrived) in rural New South Wales, Australia

Published: 2008

Time frame: 2002-2005 with monthly measurements

Mean nickel concentration was calculated to be 0.03 mg/L. The trend over the three years is displayed in the figure below.

References:

http://www.academia.edu/470880/Remediation_of_heavy_metals_in_drinking_water_and_wastewater_treatment_systems_Processes_and_applications

• Current Remediation techniques

Pengpeng Grimshaw, Joseph M. Calo, George Hradil. Cyclic electrowinning/precipitation (CEP) system for the removal of heavy metal mixtures from aqueous solutions. Chemical Engineering Journal, 2011; 175: 103 DOI: 10.1016/j.cej.2011.09.062

• Current Remediation - Electrowinning

Brown University. "Novel device removes heavy metals from water." ScienceDaily. ScienceDaily, 18 December 2011. <www.sciencedaily.com/releases/2011/12/111216150303.htm>.

• Current Remediation - Electrowinning

http://www.epa.gov/ttnchie1/le/nickel.pdf

2.Sullivan, R. J. (Litton Systems, Inc.) Air Pollution Aspects of

Nickel and Its Compounds. NTIS No. PB188070. September 1969. p.18.

3. Nriagu, J. O. ed. Nickel in the Environment. John Wiley and Sons, Inc., New York. 1980. p. 52.

4.Kirk-Othmer Encyclopedia of Chemical Technology. Third Edition. Volume 15. John Wiley and Sons, Inc. New York. 1980. pp.787-797.

5.Nriagu, J. O. ed. Nickel in the Environment. John Wiley and Sons, Inc., New York. 1980. p. 55.

AUS paper:

http://www.publish.csiro.au/?act=view_file&file_id=NB97043.pdf

4. World Health Organization. Nickel in drinking-water (WHO/SDE/WSH/05.08/55). Available from:

http://www.who.int/water_sanitation_health/gdwqrevision/nickel2005.pdf (Cited 24 October 2008.)

7. Christensen OB, Lagesson V. Nickel concentration of blood and urine after oral administration. Ann Clin Lab Sci 1981; 11: 119–25.

8. Committee on Toxicity of Chemicals in Food Consumer Products and the Environment. Nickel leaching from kettle elements into boiled water. London: Committee onToxicity; 2003. Available from: http://www.food.gov.uk/multimedia/pdfs/2003-02.pdf (Cited 24 October 2008.)

15. Expert Group on Vitamins and Minerals (EVM). Risk assessment: Nickel. London: EVM; 2003. Available from: http://www.food.gov.uk/multimedia/pdfs/evm_nickel.pdf (Cited 24 October 2008.)

16. Beattie PE, Green C, Lowe G, Lewis-Jones MS. Which children should we patch test? Clin Exp Dermatol 2006; 32: 6–11.

17. Militello G, Jacob SE, Crawford GH. Allergic contact dermatitis in children. Curr Opin Pediatr 2006; 18: 385–90. doi:10.1097/01.mop.0000236387.56709.6d

18. Silverberg NB, Licht J, Friedler S et al. Nickel contact hypersensitivity in children. Pediatr Dermatol 2002; 19: 110–3. doi:10.1046/j.1525-1470.2002.00057.x

13. Nielsen GD, Soderberg U, Jorgensen PJ et al. Absorption and retention of nickel from drinking water in relation to food intake and nickel sensitivity. Toxicol Appl Pharmacol 1999; 154: 67–75. doi:10.1006/taap.1998.8577

Misc: Need another reference?

http://www.who.int/water_sanitation_health/gdwqrevision/nickel2005.pdf